Harvested grain may be dried and stored for extended lengths of time in grain silos or grain bins, because of fluctuating market conditions. Additionally, moist grain may be held in bins and then heated with forced air to extract the moisture. Grain bins typically include a cylindrical body and a conical roof. The body can be a peripheral wall typically comprised of bolted or welded, smooth or corrugated wall panels. The conical roof can have a 20-40 degree slope, and is typically comprised of pie-shaped or radial roof panels with integrated ribs or stiffeners along the two long sides of the panels. These ribs provide strength and stiffness to the panels, allowing them to span between the storage structure's walls and a top annular ring collar or to intermediate structural elements located beneath or above the panels.
Grain is typically loaded into these structures through a fill hole at the top of the roof and unloaded via an under floor auger system accessed through operable floor sumps. Because grain may be stored for a relatively long time, methods for preserving the condition of the grain against moisture, temperature, and insects are used. To aid in preserving grain against moisture, grain storage structures typically employ an under floor aeration system, utilizing fans which distribute air horizontally through a plenum space, vertically through a perforated floor into the grain mass, and out through vents located in the roof of the structure.
The roof must be structured to accommodate snow and wind loads while being suitably simple to construct and inexpensive in material costs.